ALARM REACTION PATTERNS BY PILOTS AS A FUNCTION OF REACTION MODALITY

Past research has demonstrated that operators may lose faith in an ala rm system that they deem unreliable. This cry-wolf effect is manifeste d by slower and less frequent alarm responses. This research examined the effect of reaction modality (manual or vocal) on reactions to alar ms of moderate reliability. Twenty-four pilots from the Madison County , Alabama, area performed tracking and monitoring tasks from the Multi -Attribute Task Battery (Parasuraman & Mouloua, 1987) while being pres ented with alarms, 75% of which were true. Pilots reacted to the alarm s during one session using key presses and during another session usin g voice-activated responses. Analysis of variance and t tests were use d to compare speed, accuracy, and frequency of primary and secondary t ask performances between vocal and manual alarm reactions. Results ind icated that participants reacted to alarms more quickly in the manual mode than in the vocal mode; however, participants responded to a grea ter number of alarms vocally than manually. The results are discussed with regard to human performance theory and aviation applications.